1. Field of the Invention
The present invention relates generally to magnetoresistive (MR) sensor elements employed within magnetic data storage and retrieval. More particularly, the present invention relates to methods for forming with enhanced dimensional uniformity magnetoresistive (MR) layers employed within magnetoresistive (MR) sensor elements employed within magnetic data storage and retrieval.
2. Description of the Related Art
The recent and continuing advances in computer and information technology have been made possible not only by the correlating advances in the functionality, reliability and speed of semiconductor integrated circuits, but also by the correlating advances in the storage density and reliability of direct access storage devices (DASDs) employed in digitally encoded magnetic data storage and retrieval.
Storage density of direct access storage devices (DASDs) is typically determined as areal storage density of a magnetic data storage medium formed upon a rotating magnetic data storage disk within a direct access storage device (DASD) magnetic data storage enclosure. The areal storage density of the magnetic data storage medium is defined largely by the track width, the track spacing and the linear magnetic domain density within the magnetic data storage medium. The track width, the track spacing and the linear magnetic domain density within the magnetic data storage medium are in turn determined by several principal factors, including but not limited to: (1) the magnetic read-write characteristics of a magnetic read-write head employed in reading and writing digitally encoded magnetic data from and into the magnetic data storage medium; (2) the magnetic domain characteristics of the magnetic data storage medium; and (3) the separation distance of the magnetic read-write head from the magnetic data storage medium.
With regard to the magnetic read-write characteristics of magnetic read-write heads employed in reading and writing digitally encoded magnetic data from and into a magnetic data storage medium, it is known in the art of magnetic read-write head fabrication that magnetoresistive (MR) sensor elements employed within magnetoresistive (MR) read-write heads are generally superior to other types of magnetic sensor elements when employed in retrieving digitally encoded magnetic data from a magnetic data storage medium. In that regard, magnetoresistive (MR) sensor elements are generally regarded as superior since magnetoresistive (MR) sensor elements are known in the art to provide high output digital read signal amplitudes, with good linear resolution, independent of a relative velocity of a magnetic data storage medium with respect to a magnetoresistive (MR) read-write head having the magnetoresistive (MR) sensor element incorporated therein.
While magnetoresistive (MR) sensor elements are thus desirable within the art of magnetic data storage and retrieval, magnetoresistive (MR) sensor elements are nonetheless not fabricated entirely without problems within the art of magnetoresistive (MR) sensor element fabrication. In particular, it is often difficult to fabricate within a magnetoresistive (MR) sensor element magnetic layers, such as but not limited to magnetoresistive (MR) layers, with enhanced dimensional uniformity, such enhanced dimensional uniformity including but not limited to enhanced dimensional overlay uniformity.
It is thus towards the goal of providing for use within magnetoresistive (MR) sensor element fabrication methods for forming with enhanced dimensional uniformity magnetic layers, such as magnetoresistive (MR) layers, within those magnetoresistive (MR) sensor elements, that the present invention is directed.
Various magnetoresistive (MR) sensor elements having desirable properties, as well as higher level magnetic data storage enclosure fabrications fabricated incorporating those magnetoresistive (MR) sensor elements having the desirable properties, have been disclosed in the art of magnetoresistive (MR) sensor element fabrication.
For example, Dieny et al., in U.S. Pat. No. 5,159,513, disclose a magnetoresistive (MR) sensor element which provides a desirably enhanced magnetoresistive (MR) response when detecting magnetic data encoded at a diminished magnetic data encoding field strength. The magnetoresistive (MR) sensor element is a spin valve magnetoresistive (SVMR) sensor element wherein at least one of a pair of ferromagnetic layers within the spin valve magnetoresistive (SVMR) sensor element is formed of either cobalt or a cobalt alloy.
In addition, Lee et al., in U.S. Pat. No. 5,731,936, disclose a magnetoresistive (MR) sensor element which exhibits an enhanced magnetoresistive (MR) coefficient (i.e. an enhanced magnetoresistive (MR) resistivity sensitivity), as well as an improved thermal stability. To effect the foregoing results, the magnetoresistive (MR) sensor element employs one or more chromium based spacer layers interfacially adjacent a nickel-iron permalloy alloy magnetoresistive (MR) layer within the magnetoresistive (MR) sensor element.
Further, Ravipati et al., in U.S. Pat. No. 5,739,990, disclose a magnetoresistive (MR) sensor element having an improved electrical bias, as well as a low resistivity. The magnetoresistive (MR) sensor element, which may be an anisotropic magnetoresistive (AMR) sensor element or a spin valve magnetoresistive (SVMR) sensor element, employs: (1) a pair of patterned conductor lead layers formed abutting at least one magnetoresistive (MR) layer within the magnetoresistive (MR) sensor element, in conjunction with; (2) a pair of patterned longitudinal magnetic bias layers which are formed in contact with the pair of patterned conductor lead layers but overlapping the at least one patterned magnetoresistive (MR) layer to define a trackwidth of the magnetoresistive (MR) sensor element.
Finally, Hoshiya et al., in U.S. Pat. No. 5,843,589, discloses a magnetic material laminate and a magnetoresistive (MR) sensor element fabricated employing the magnetic material laminate, wherein the magnetoresistive (MR) sensor element provides an enhanced signal amplitude and an enhanced signal-to-noise ratio, with enhanced reliability. To realize the foregoing objects, the magnetoresistive (MR) sensor element employs as the magnetic material laminate a cobalt or a cobalt alloy ferromagnetic magnetoresistive (MR) material layer formed in contact with a chromium-manganese alloy anti-ferromagnetic magnetic biasing layer within the magnetoresistive (MR) sensor element.
Desirable in the art of magnetoresistive (MR) sensor element fabrication are additional methods and materials which may be employed to form within the art of magnetoresistive (MR) sensor element fabrication magnetic layers, such as magnetoresistive (MR) layers, with enhanced dimensional uniformity.
It is toward the foregoing object that the present invention is directed.
A first object of the present invention is to provide a method for fabricating a magnetoresistive (MR) sensor element.
A second object of the present invention is to provide a method in accord with the first object of the present invention, wherein a magnetic layer within the magnetoresistive (MR) sensor element is fabricated with enhanced dimensional uniformity.
A third object of the present invention is to provide a method in accord with the first object of the present invention and the second object of the present invention, which method is readily commercially implemented.
In accord with the present invention, there is provided by the present invention a method for forming a magnetic layer. To practice the method of the present invention, there is first provided a substrate. There is then formed over the substrate a magnetic layer formed of a magnetic material, where the magnetic material has a first value of a magnetic characteristic of the magnetic material. There is then ion implanted, while employing an ion implant method, at least a portion of the magnetic layer to form at least an ion implanted portion of the magnetic layer, where the at least the ion implanted portion of the magnetic layer is formed of an ion implanted magnetic material, and where the ion implanted magnetic material has a second value of the magnetic characteristic of the magnetic material different from the first value of the magnetic characteristic of the magnetic material.
The present invention provides a method for fabricating a magnetoresistive (MR) sensor element, wherein a magnetic layer within the magnetoresistive (MR) sensor element is fabricated with enhanced dimensional uniformity. The method of the present invention realizes the foregoing object by employing when fabricating the magnetic layer an ion implant method which provides a second value of a magnetic characteristic of an ion implanted magnetic material from which is formed an ion implanted magnetic layer different in comparison with a first value of a magnetic characteristic of a magnetic material from which is formed a magnetic layer from which in turn is formed via the ion implant method the ion implanted magnetic layer (i.e. a magnetic characteristic of a magnetic layer is changed by ion implanting the magnetic layer). Since the ion implant method may be undertaken as a masked ion implant method with controlled ion implant dimensional bias with respect to an ion implant mask layer employed within the ion implant method, there may be fabricated while employing the present invention a magnetic layer within a magnetoresistive (MR) sensor element with enhanced dimensional uniformity.
The method of the present invention is readily commercially implemented. The present invention employs methods and materials, which although not necessarily previously employed within the art of magnetoresistive (MR) sensor element fabrication, are, as illustrated within the Description of the Preferred Embodiment which follows, readily adapted to the art of magnetoresistive (R) sensor element fabrication. Since the present invention is directed towards the adaptation of methods at least generally known within other arts, rather than developing entirely new methods and materials, the method of the present invention is comparatively readily commercially implemented.